Tier Assessment Research Articles

Modelling pesticide concentrations in Japanese paddy fields using the RICEWQ model

Increasing concerns about plant protection products in surface waters have highlighted the importance of pesticide monitoring and modelling, both nowadays integral components of the pesticide registration process. The Rice Water Quality (RICEWQ) model predicts the fate and transport of pesticides under various paddy environmental conditions. The model has been used widely for regulatory purpose in the U.S., while its use in Europe has been limited to regulatory submissions, despite multiple recommendations to adopt RICEWQ as a high tier assessment model for regulatory purposes. The applicability of the RICEWQ model under Japanese agricultural conditions remains unexplored. This study leverages field experimental data to evaluate the RICEWQ model's capability to simulate daily concentrations of two herbicides, mefenacet and pretilachlor, in paddy water and paddy soil in Japan.The RICEWQ model provided a reasonable level of performance for predicting the fate and transport of the two herbicides by ensuring that the simulated daily water balance corresponded with field observations and with minor pesticide-specific calibration. To further improve the performance of the simulations, we implemented a straightforward calibration framework. Calibrating the RICEWQ model improved the accuracy of all simulations; for both herbicides and in both paddy water and paddy soil compartments, the lowest Nash-Sutcliffe efficiency achieved was 0.725, demonstrating excellent performance. However, the RICEWQ model consistently underestimated the peak concentrations of herbicides in paddy water within the first three days of simulation. Simulation results suggested that approximately 50 % of the total applied herbicide was lost from the paddy system. Increasing the duration of the water holding period after pesticide application or increasing the storage capacity of the rice field via excess water storage depth management has the potential to reduce greatly herbicide loss to below 10 % of the total applied herbicide.

Use of dislodgeable foliar residue studies for the evaluation of isomerization potential of active substances for non-dietary risk assessment.

When assessing the non-dietary risks for operators, workers, bystanders and residents to active substances in plant protection products (PPPs) that contain stereoisomers, the EFSA guidance on stereoisomers recommends the application of uncertainty factors when the initial ratio of stereoisomers undergoes a significant stereoisomeric excess change of more than 10%. This precautionary approach may be over-conservative in cases where the change in isomers is due to differences in their degradation rates rather than conversion of one isomer to a potentially more toxic isomer. Therefore, the impact of isomeric composition in non-dietary risk assessments of PPPs was evaluated, with particular emphasis on dislodgeable foliar residues (DFR) data and potential enantioselective degradation processes. Hypothetical outcomes are discussed as well as an evaluation of data for 5 compounds from a total of 35 DFR studies conducted under GLP, aimed at deriving DFR values for higher tier assessments. The findings indicate that possible isomerization of the active substance on leaves can be detected in DFR studies, which is essential for assessing risks to workers and residents. The results of this evaluation highlight the potential for over-conservatism of the current EFSA method for calculating uncertainty factors in non-dietary risk assessments. The EFSA method's reliance on worst-case assumptions, coupled with the lack of a formal statistical basis, can lead to overestimation of exposure, as illustrated in our theoretical considerations and supported by empirical data from DFR studies. To address this, we propose an alternative approach to evaluating risk considering both degradation and interconversion rates.

Effectively scaling assessment efforts in the evaluation of environmental risks of offshore produced water discharges using a tiered approach

For offshore oil and gas production facilities, overboard disposal of treated produced water (PW) remains a principal waste management option, and regulatory frameworks have been established to manage these discharges. Risk-based assessment (RBA) of PW, which aims to quantify potential impacts on the environment, has been adopted in some regulatory systems, but is also applied by oil and gas operators as part of their risk management systems. In 2020, the International Association of Oil and Gas Producers published a guidance document, including a four-tiered assessment framework aiming for a broader understanding and consistent application of PW RBA globally. The current study reviewed case studies and categorised them along the proposed assessment tiers. Regulatory developments are shown to be key drivers for the application of PW RBA globally, but required tools are often to resource intense for early risk screening. The proposed framework promotes the use of existing data, read-across techniques, and non-animal testing in two initial screening tiers, characterised by little to no sampling. In addition, it allows to refine higher tier assessments through the application of species sensitivity distributions and the inclusion of exposure time to avoid conservative assessment factors. This enables assessments to better approximate observations from field verification, included as a final tier to determine the level of discernible effects. The proposed tiered assessment approach can be considered a novel way to scale assessment efforts to the situation especially in cases where resources are limited, priorities for further investigations need to be set, rapid evaluation of hazard levels is required, sampling logistics and transport of large volumes is complicated and/or there is an opportunity for reduced animal testing. This makes early assessments more effective and ensures logical and efficient actions are triggered for understanding and managing environmental risks of produced water discharges.

Development of a soil exposure assessment for plant protection products in Brazil: Requirements, options, and recommendations.

The Brazilian Environmental Authority (IBAMA) has recently identified soil organisms as a priority area for risk assessment development for plant protection products. This includes consideration of which species in soil fauna are important to be tested for risk assessment purposes, which ecotoxicological tests should be used, and which exposure models would be suitable, considering Brazilian soils, local agricultural practices, and local biodiversity. In this brief communication, we present proposals and recommendations for the selection of appropriate regulatory exposure assessment techniques to support initial or foundation tier assessment. Integr Environ Assess Manag 2023;19:862-869. © 2022 FMC Corporation, Syngenta, Adama, Bayer AG, BASF SE. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

A national probabilistic characterization of local crop proximity and density for refining US screening level exposure estimates of pesticides in surface water arising from agricultural use

Rising world population and changing diets are increasing the need for efficient and effective food and fiber production. Pesticides are used across the US to control pests and improve food yield and quality, but these benefits are offset by their potential to reach and possibly impact aquatic or terrestrial ecosystems. Regulatory agencies rely on prospective exposure models that often start with conservative simplifying assumptions that are refined with additional information if needed. The USEPA ecological risk assessment framework for pesticides assumes, at screening level, that 100% of the area draining to a water body is cropped. However, at the grower’s real-world scale, this simplifying assumption is generally not realistic and should be refined for higher tier assessment. The present study developed a US-wide spatially explicit analysis of crop density and proximity to surface waters to characterize the potential for pyrethroid insecticides to enter flowing surface waters. Reliable, transparent, and publicly available government spatial cropping and hydrology datasets were employed at the catchment-scale across the full extent of agricultural production in the US were used to generate fifteen novel crop-specific probabilistic distributions describing the extent and proximity of each crop to the flowing water body defining small catchments. These were used to refine estimated environmental concentrations using USEPA standard regulatory scenarios to evaluate the importance of considering agricultural landscapes when refining aquatic pesticide concentrations. Incorporating these real-world probabilities of crop occurrence and proximity showed that, while potential maximal aquatic exposure concentrations are unchanged, the probability of exceeding regulatory decision-making concentration endpoints is much lower than predicted by standard assumptions (e.g., 1.9 to ~50-fold reductions by crop for 90% of catchments). Additionally, we show that the relative ranking of crops by their aquatic pesticide exposure potential may change from that indicated when cropping density and proximity are considered.

Mobility in the context of exposure-based assessment of chemicals for drinking water resourceprotection.

In order to protect European Union (EU) drinking water resources from chemical contamination, criteria for identifying persistent, mobile, and toxic (PMT) chemicals and very persistent and very mobile (vPvM) chemicals under the EU REACH Regulation were proposed by the German Environment Agency (Umweltbundesamt-UBA). Additionally, new hazard classes for PMT and vPvM substances in the revised EU classification, labeling, and packaging (CLP Regulation) are intended. Therefore, a reliable approach in theidentificationof potential drinking water resource contaminants is needed. The scientific basis of the property-based PMT/vPvM criteria, focusing on mobility, which dictates the migration of chemicaldrinking water sources, was evaluated, and a critical analysis of the deviation of sorption metrics from simple behavior was carried out. Based on our evaluation, a Koc may be used for nonionic substances on a screening level only, requiring a higher tier assessment. It is considered inappropriate for hydrophilic and ionizable chemicals, particularly for soils with low organic carbon contents. The nonextractable residue formation is complex and not well understood but remains significant in limiting the mobility of chemicals through soils and sediments. In order to inform the EU commission's work on the introduction of new hazard classes for PMT and vPvM substances into the European legislation, the derivation of a tiered approach is proposed,which utilizes the weight of evidence available, with adoption of appropriate higher tier models commensurate with the nature of the substance and the data available. Integr Environ Assess Manag 2023;19:775-791. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Application of a Screening-Level Pollinator Risk Assessment Framework to Trisiloxane Polyether Surfactants.

Regulatory requirements exist to assess the potential impacts of pesticides on insect pollinators, but "inert," coformulants to pesticide formulations are not included in standard regulatory risk assessments. Some publications in the open literature have suggested that the agricultural uses of "inert" ingredients, including trisiloxane polyether surfactants, may result in adverse effects on pollinators. We conducted a screening-level risk assessment to evaluate the potential risk to insect pollinators, using honey bees (Apis mellifera) as a surrogate, from exposure to three trisiloxane polyether surfactants based on agricultural application scenarios following the current US Environmental Protection Agency (USEPA) guidance. The exposure assessment included data from two sources: (1) use data reported in California's (USA) Pesticide Use Registry (PUR) database for all crops, and (2) an almond orchard residue study conducted using the three trisiloxane polyether surfactants. Honey bee laboratory studies with each of the trisiloxane polyether surfactants reported 50% lethal doses (LD50s) or no adverse effect levels, which were used as the effects inputs to BeeREX. The exposure and toxicity data were combined to estimate potential honey bee risk based on the determination of acute and chronic risk quotients (RQs) for larval and adult life stages. The RQs calculated using both the PUR use rates as well as the application rates and peak measured residues from the almond orchard residue study were below the USEPA acute and chronic levels of concern (acute, 0.4; chronic, 1.0). Based on these results, the use of these three trisiloxane polyether surfactants in agricultural use settings can be considered minimal risk to insect pollinators, and higher tier assessment is unnecessary for the characterization of risk. Environ Toxicol Chem 2022;41:3084-3094. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

A PETAR method for risk assessment of human health and environment on the regional scale.

Risk assessments are necessary to effectively reveal the state of the degradation of living environments on a regional scale. However, risk assessments are often limited by time, cost, and technology, which make conducting effective evaluations difficult. Thus, in this study, the procedure for ecological tiered assessment of risk (PETAR) method was used to analyze the human health and environmental risks in Daye, China. This method first used the United States Environmental Protection Agency's risk assessment approach to qualitatively determine the risk sources, pressures, receptors, and effect endpoints and constructed a conceptual model of threats to the human living environment. Each risk-prone subregion was then evaluated using the fuzzy logic method. Next, a quantitative assessment was conducted for the subregions with the most serious environmental degradation. Finally, quantitative analyses were performed to verify the original hypotheses. The results showed that the high-risk areas were distributed in the industrial regions of Daye, wherein mining and processing clusters and mining settlements are widespread and confirmed the locations of the particular subregions with the most serious human health and environmental risks. This study also validated the practicality of the PETAR method for human health risk assessments in mining areas with large-scale, multifactor, and multihazard paths. Integr Environ Assess Manag 2023;19:239-253. © 2022 SETAC.

Assessment of human exposure to environmental sources of lead arising from the lead battery manufacturing and recycling sector in Europe: demonstration of a tiered approach in a case study.

Standard approaches for the assessment of Man via the Environment exposure are designed to be conservative. However, propagating these exposures into health impact assessment might lead to questionable socio-economic costs. The objective of this study was to develop a novel tiered modelling approach to assess human exposure to lead (Pb) via the environment. The approach starts in Tier 1 from EUSES modelling approach, modified with metal specific transfer factors. The generic Tier 2 approach uses the higher tier model GPM for air quality, and dietary exposure modelling based on EFSA's Comprehensive Food Database, in combination with crop specific transfer factors. Tier 3 considers additional site-specific information such as proximity of inhabitants and agricultural activities in relation to industrial sites. This tiered modelling approach was applied to a case study of 50 lead battery manufacturing and recycling sites across Europe. Data sets from general population human biomonitoring studies were used to compare the predicted additional bioburden of Pb resulting from lead battery manufacturing and recycling. The higher tier assessments were able to demonstrate a >20-fold reduction in modelled Pb exposure compared to default assumptions made in Tier 1. Leading to better estimates for socio-economic costs in health impact assessment.

Building Preservice Teachers’ Diagnostic Competence: An Exploratory Study in the Domain of Fractions

In this study, we explored elementary preservice teachers’ (PSTs’) competence to make diagnostic inferences about students’ levels of understanding of fractions and their approaches to developing appropriate tiered assessment items. Although recent studies have investigated beginning teachers’ diagnostic competency, teachers’ ability to design and evaluate diagnostic assessment items has remained largely underexplored. Fifty-seven PSTs, who enrolled in a mathematics methods course at a midwestern university in the U.S., participated in developing and attempting to differentiate diagnostic assessment items considering individual students’ varied levels of understanding. An inductive content analysis approach was used in identifying general patterns of PSTs’ approaches and strategies in designing and revising tiered assessment items. Our findings revealed the following: (a) the PSTs were well versed in students’ cognitive difficulties; (b) when modifying the core questions to be more or less difficult, the PSTs predominantly used strategies related to procedural fluency of the questions; and (c) some strategies PSTs used to modify questions did not necessarily yield the intended level of difficulty. Further, we discussed the challenges and opportunities teacher education programs face in teaching PSTs how to effectively design tiered assessment items.

Pesticide residues in the pollen and nectar of oilseed rape (Brassica napus L.) and their potential risks to honey bees

Research evidence suggests that pesticide residues are one of the leading potential causes of the decline in pollinators, especially during vulnerable periods such as foraging in the early springtime. In China, no research quantifies pesticide residues in the nectar and pollen of honey bee colonies during this period or examines the potential risks and toxicity of pesticides to honey bees. Oilseed rape is one of the first and primary bee-attractive plants in most parts of China. Here, we investigated the pesticide residues in the oilseed rape of the years 2017 and 2018 in China. The hazard quotient (HQ) from pollen and nectar and the BeeREX risk assessment were used to evaluate the potential risks of the pesticide residues to honey bees. We detected 48 pesticides in pollen samples and 34 chemicals in nectar samples. The maximum pollen HQ (PHQ) values (contact or oral) ranged from 0.16 to 706,421, and the maximum nectar HQ (NHQ) values (contact or oral) ranged from 0.07 to 185,135. In particular, carbofuran, cyfluthrin, deltamethrin, and fenpropathrin have relatively high PHQ and NHQ values. Our results indicated that further investigation of nearly half of the tested compounds is needed because their PHQ or NHQ values are more than 50. Especially cyfluthrin and carbofuran need advanced tier assessment due to their maximum RQ (risk quotient) values exceeding the level of concern. These results provide valuable guidance for protecting bees and other pollinators in China.

Application of screening tools for environmental hazard and risk to support assessment and subsequent prioritization of effluent discharges from the oil and gas industry

Assessment and management of effluent discharges are key to avoid environmental deterioration. Often compliance with discharge regulations and permits is based on a limited set of chemical parameters, while information on whole-effluent hazardous properties (toxicity, bioaccumulation potential, persistence) and environmental risks is lacking. The need to collect those data and to become more effective in quickly identifying high risk activities, without extensive laboratory testing, has led to the development of screening tools to complement information on chemical composition. A simple, Tier-1 screening 'Toolbox' is proposed which is comprised of Solid Phase Micro Extraction with Gas Chromatographic analysis (SPME-GC), the in-vitro ecotoxicity assay Microtox and a simple weathering assay. When combined with dilution modelling screening level risk assessments can be performed providing additional lines of evidence to support a Weight of Evidence type of analysis. This enables prioritisation of discharges that may be deemed to require higher tier assessment. The Toolbox was trialled on a number of produced water samples collected from offshore oil and gas facilities and effluents from petroleum processing and manufacturing sites. In contrast to what has been reported for petroleum products, results showed only moderate correlation between bioavailable hydrocarbons (bHC) and toxicity, which might be related to the possible presence of toxic contaminants from other chemical classes or to methodological issues such as sub-optimal conditions during transport. The methods employed were quick, inexpensive and simple to conduct. They require relatively small volumes of sample, which is especially advantageous when evaluating discharges from remote offshore facilities. The Toolbox adds valuable information on whole effluent properties to existing data e.g. on chemical composition which can improve understanding of which discharges are more likely to pose a risk to the environment and so require further investigation or risk management. This article is protected by copyright. All rights reserved.

Comparing the European Union System for the Evaluation of Substances (EUSES) environmental exposure calculations with monitoring data for alkyl sulphate surfactants

BackgroundThe European surfactant and detergent industry initiated a project to conduct an EUSES-based environmental exposure assessment for the total volume of alkyl sulfate (AS) surfactants, and to verify if the EUSES assessment leads to a realistic prediction of the environmental exposure or to an over- respectively under-estimation of the environmental concentrations of the surfactants. Verification of the EUSES environmental concentration prediction (Clocaleffluent) was carried out by benchmarking them against environmental monitoring data. Recently published data from the United States of America adjusted to the European Union (EU) frame conditions were used for the assessment, as for the EU only historical data from the mid-1990s are available. In addition to the standard (default) EUSES assessment, a higher tier assessment using substance-specific properties, particularly increased biodegradation rates (192 per day instead of the default of 24 per day for WWTP), was conducted.ResultsA figure of 178,400 tonnes of AS was established as the total maximum volume (2016) handled annually in Europe. This total volume includes the volumes from all EU manufacturers and all registered AS > 100 t/a, as well as the amount of AS contained in EU REACH registered alkyl ether sulfates (AES). The total tonnage was split and assigned to the different uses as reported to ECHA in the C12 AS, Na (151-21-3) registration dossier in 2010. The EUSES calculation was limited to widespread (professional and consumer) uses, covering in total 97,889 t of AS homologues. The EUSES calculation gave a Clocaleffluent of 335 µg/L for the SimpleTreat “readily” biodegradation rate default and a Clocaleffluent of 44.6 µg/L for the AS-specific degradation rates. Recent US monitoring data showed a mean effluent concentration of 4.24 µg alkyl sulfates/L (∑ C12 + C14 + C16 homologues). Taking into account the different annual per capita AS use (including AS from AES) in the US (295 g) and the EU (348 g), the daily per capita water use (EU 200 L, US 408 L), and the WWTP efficiency in the EU and the US (comparable), an US to EU adjustment factor of 2.4 was established. Application of the adjustment factor to the US monitoring data resulted in a calculated EU mean effluent concentration = 10.18 µg alkyl sulfates/L (∑ C12, C14, C16 homologues). This value was used as an independent benchmark for the EUSES calculations.ConclusionsComparing the predicted Clocaleffluent = 335 µg alkyl sulfates/L (SimpleTreat default) and a Clocaleffluent = 44.6 µg Alkyl Sulfates/L (AS-specific degradation rates) with the 10.18 µg alkyl sulfates/L from the adjusted monitoring data it is evident, that the EUSES calculation overestimates the AS environmental exposure by factors of > 32 and > 4, respectively. Taking into consideration, that only widespread uses (covering only 50% of the total AS volume) were included in the EUSES calculation, the overestimation of the default exposure by a factor of 4 is still conservative, despite the fact, that eightfold higher, substance-specific biodegradation rates were used. In conclusion, using the 2010 C12-AS REACH dossier (CAS-No. 151-21-3) as an example, it has been shown, that EUSES model exposure calculations using default biodegradation rates significantly overestimate effluent concentrations.

Development of a Web-Based Toolbox to Support Quantitative In-Vitro-to-In-Vivo Extrapolations (QIVIVE) within Nonanimal Testing Strategies.

The goal of the present study was to develop an online web-based toolbox that contains generic physiologically based kinetic (PBK) models for rats and humans, including underlying calculation tools to predict plasma protein binding and tissue:plasma distribution, to be used for quantitative in-vitro-to-in-vivo extrapolations (QIVIVE). The PBK models within the toolbox allow first estimations of internal plasma and tissue concentrations of chemicals to be made, based on the logP and pKa of the chemicals and values for intestinal uptake and intrinsic hepatic clearance. As a case study, the toolbox was used to predict oral equivalent doses of in vitro ToxCast bioactivity data for the food additives methylparaben, propyl gallate, octyl gallate, and dodecyl gallate. These oral equivalent doses were subsequently compared with human exposure estimates, as a low tier assessment allowing prioritization for further assessment. The results revealed that daily intake levels of especially propyl gallate can lead to internal plasma concentrations that are close to in vitro biological effect concentrations, particularly with respect to the inhibition of human thyroid peroxidase (TPO). Estrogenic effects were not considered likely to be induced by the food additives, as daily exposure levels of the different compounds remained 2 orders of magnitude below the oral equivalent doses for in vitro estrogen receptor activation. Overall, the results of the study show how the toolbox, which is freely accessible through www.qivivetools.wur.nl, can be used to obtain initial internal dose estimates of chemicals and to prioritize chemicals for further assessment, based on the comparison of oral equivalent doses of in vitro biological activity data with human exposure levels.

Are In Silico Approaches Applicable As a First Step for the Prediction of e-Liquid Toxicity in e-Cigarettes?

Recent studies have raised concerns about e-cigarette liquid inhalation toxicity by reporting the presence of chemicals with European Union CLP toxicity classification. In this scenario, the regulatory context is still developing and is not yet up to date with vaping current reality. Due to the paucity of toxicological studies, robust data regarding which components in e-liquids exhibit potential toxicities, are still inconsistent. In this study we applied computational methods for estimating the toxicity of poorly studied chemicals as a useful tool for predicting the acute toxicity of chemicals contained in e-liquids. The purpose of this study was 3-fold: (a) to provide a lower tier assessment of the potential health concerns associated with e-liquid ingredients, (b) to prioritize e-liquid ingredients by calculating the e-tox index, and (c) to estimate acute toxicity of e-liquid mixtures. QSAR models were generated using QSARINS software to fill the acute toxicity data gap of 264 e-liquid ingredients. As a second step, the potential acute toxicity of e-liquids mixtures was evaluated. Our preliminary data suggest that a computational approach may serve as a roadmap to enable regulatory bodies to better regulate e-liquid composition and to contribute to consumer health protection.

Overcoming Challenges of Incorporating Higher Tier Data in Ecological Risk Assessments and Risk Management of Pesticides in the United States: Findings and Recommendations from the 2017 Workshop on Regulation and Innovation in Agriculture.

ABSTRACTPesticide regulation requires regulatory authorities to assess the potential ecological risk of pesticides submitted for registration, and most risk assessment schemes use a tiered testing and assessment approach. Standardized ecotoxicity tests, environmental fate studies, and exposure models are used at lower tiers and follow well‐defined methods for assessing risk. If a lower tier assessment indicates that the pesticide may pose an ecological risk, higher tier studies using more environmentally realistic conditions or assumptions can be performed to refine the risk assessment and inform risk management options. However, there is limited guidance in the United States on options to refine an assessment and how the data will be incorporated into the risk assessment and risk management processes. To overcome challenges to incorporation of higher tier data into ecological risk assessments and risk management of pesticides, a workshop was held in Raleigh, North Carolina. Attendees included representatives from the United States Environmental Protection Agency, United States Department of Agriculture, National Oceanic and Atmospheric Administration, universities, commodity groups, consultants, nonprofit organizations, and the crop protection industry. Key recommendations emphasized the need for 1) more effective, timely, open communication among registrants, risk assessors, and risk managers earlier in the registration process to identify specific protection goals, address areas of potential concern where higher tier studies or assessments may be required, and if a higher tier study is necessary that there is agreement on study design; 2) minimizing the complexity of study designs while retaining high value to the risk assessment and risk management process; 3) greater transparency regarding critical factors utilized in risk management decisions with clearly defined protection goals that are operational; and 4) retrospective analyses of success–failure learnings on the acceptability of higher tier studies to help inform registrants on how to improve the application of such studies to risk assessments and the risk management process. Integr Environ Assess Manag 2019;15:714–725. © 2019 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

3194 Workforce Engagement and Resilience (WE-R): A Framework for Innovating Clinical Research Careers

OBJECTIVES/SPECIFIC AIMS: 1.Assess changes in clinical research workforce landscape at Duke 2.Optimize and evaluate efficacy of a tier advancement process for clinical research career progression at Duke 3.Implement CRP engagement as a change management mechanism for workforce innovation METHODS/STUDY POPULATION: We evaluated 857 clinical research positions at Duke to understand changes in the workforce (demographics, numbers in each position and tier) since implementing the tier advancement process in 2016. To understand the efficacy of the tier assessment process, data from a subset of this population (n=84) who underwent the advancement process was examined for success rate. Individual employees and their managers were surveyed to understand their perception of the advancement process and identify areas for improvement. We also describe implementation of multiple mechanisms of community engagement to manage expectations around the tier advancement process and to provide opportunities for employees to self-manage their career planning, including portfolio planning and leadership opportunities. RESULTS/ANTICIPATED RESULTS: Whereas the clinical research workforce has grown by 5.5% since tiering began (2016, n=810; 2018 n=857). Nearly 13% of that growth has been in managerial or senior positions (2016, n=111; 2018 n=127). Distributions across job classifications changed only slightly, representing realignment of positions with study-level responsibilities over department-level responsibilities. Notably, clinical research nurses (CRNC & CRNC Sr.) was the only category including tiered and non-tiered positions to drop overall numbers between 2016 (n = 136) and 2018 (n=115), representing a shift in the workforce from research nurses to research coordinators. General demographics (gender, age) remained largely the same. A total of 359 positions have been hired during this time frame, nearly half of which were entry-level positions (175/359): 47 of these positions represent expansion of the workforce. Of 359 new hires since 2016, 271 currently still work in one of the research roles. Of the 84 employees who underwent the tier advancement process, 84% (43/51) succeeded in tier 2 advancement, 70% (14/20) succeeded in tier 3 advancement (CRC, CRNC, and regulatory coordinators), and 77% (10/13) of research program leaders (RPLs) succeeded in achieving tier two, which is the highest tier for this group. Fifty-five employees (65%) and 32 managers responded to a voluntary feedback survey. Overall confidence in the process improved in both groups from 2016 to 2018, most notably with managers. Both groups indicated a 10 hour reduction (employees = 35hr, 2016 and 25hr 2018; managers 25hr, 2016 and 15hr 2018) in time required to complete the tier advancement process. DISCUSSION/SIGNIFICANCE OF IMPACT: The use of objectively-assessed competencies is an important step in the development of a workforce. By 1) maintaining alignment with industry standards for competencies, 2) upholding high standards, and 3) offering a consistent approach to career growth, Duke is working to develop and maintain a workforce that supports high quality research. Since the implementation of standardized job classifications and competency-based tier advancement, the positions have undergone rigorous competency-based needs evaluation. This leads to better matched jobs to study needs as well as increased standardization across the clinical research workforce. We believe that the subtle workforce shifts represent alignment of our positions with the business needs of our clinical research enterprise. Additionally, approximately 15% of our clinical research workforce has taken advantage of the opportunity to advance their own careers. We have made significant improvements in the following tier advancement processes: standardization of assessments, scoring guides, and modes; changes from LMS to a REDCap delivery of the knowledge assessments; streamlined the utilization of electronic documentation; and additional guidance for employees and managers regarding portfolio inclusions. These improvements have increased satisfaction and acceptance with the advancement process and were made possible through strategic communication across the workforce. Regular town hall meetings and focus group feedback sessions have included the clinical research community in discussions of WE-R initiatives and provided a much-needed feedback loop for process improvement and change management. Moreover, inclusion of WE-R discussion in our Research Professional Network events has provided opportunities to discuss career advancement strategies as well as volunteer opportunities to grow and demonstrate leadership competencies.

Risk assessment of biosolids-borne ciprofloxacin and azithromycin

Ciprofloxacin (CIP) and azithromycin (AZ) are commonly prescribed antibiotics for various infections in humans and are frequently detected in biosolids. Ecological and human health risks from biosolids-borne CIP and AZ are not well understood, but necessary for formulating policies on safe use and management of biosolids. A tiered integrated risk assessment (IRA), based on the World Health Organization (WHO) framework and the USEPA Part 503 Biosolids Rule, was conducted to assess human and ecological health risks from biosolids-borne CIP and AZ. The IRA utilized the hazard quotient (HQ) approach to evaluate risks to various receptors of concern (including humans, animals, and birds) in sixteen exposure pathways and three conservative biosolids land application scenarios. The scenarios consisted of (i) single-heavy (100 Mg ha−1) land application of biosolids containing 95th percentile concentrations of CIP or AZ (USEPA, 2009), (ii) long-term (annual for 40-y) land application of biosolids containing typical (median; USEPA, 2009) CIP or AZ concentrations, and (iii) long-term (annual for 40-y) land application of biosolids containing the 95th percentile concentrations of CIP or AZ. The unrealistically conservative screening level (Tier 1) assessment identified three pathways of potential concern: biosolids → soil → plant (CIP); biosolids → soil → soil organism (CIP and AZ); and biosolids → soil → soil organism → predator (CIP and AZ). Subsequent tier (refined; more realistic) assessments and pollutant limits (calculated based on the USEPA Part 503 Biosolids Rule) suggested negligible human and ecological health risks from biosolids-borne CIP and AZ under real-world biosolids application scenarios. Pollutant concentration limits were 12 mg CIP kg−1 and 2.2 mg AZ kg−1; suggesting that pollutant load tracking is not needed for the majority (75% for CIP and 90% for AZ) of USA biosolids. Biosolids-borne antibiotic resistance (currently not addressed in any risk assessment model) is the principal uncertainty limiting risk assessment of biosolids-borne antibiotics including CIP and AZ.

Guidance on quantitative pest risk assessment.

This Guidance describes a two‐phase approach for a fit‐for‐purpose method for the assessment of plant pest risk in the territory of the EU. Phase one consists of pest categorisation to determine whether the pest has the characteristics of a quarantine pest or those of a regulated non‐quarantine pest for the area of the EU. Phase two consists of pest risk assessment, which may be requested by the risk managers following the pest categorisation results. This Guidance provides a template for pest categorisation and describes in detail the use of modelling and expert knowledge elicitation to conduct a pest risk assessment. The Guidance provides support and a framework for assessors to provide quantitative estimates, together with associated uncertainties, regarding the entry, establishment, spread and impact of plant pests in the EU. The Guidance allows the effectiveness of risk reducing options (RROs) to be quantitatively assessed as an integral part of the assessment framework. A list of RROs is provided. A two‐tiered approach is proposed for the use of expert knowledge elicitation and modelling. Depending on data and resources available and the needs of risk managers, pest entry, establishment, spread and impact steps may be assessed directly, using weight of evidence and quantitative expert judgement (first tier), or they may be elaborated in substeps using quantitative models (second tier). An example of an application of the first tier approach is provided. Guidance is provided on how to derive models of appropriate complexity to conduct a second tier assessment. Each assessment is operationalised using Monte Carlo simulations that can compare scenarios for relevant factors, e.g. with or without RROs. This document provides guidance on how to compare scenarios to draw conclusions on the magnitude of pest risks and the effectiveness of RROs and on how to communicate assessment results.

Evaluation of a single extraction test to estimate the human oral bioaccessibility of potentially toxic elements in soils: Towards more robust risk assessment

Intake of soil by children and adults is a major exposure pathway to contaminants including potentially toxic elements (PTEs). However, only the fraction of PTEs released in stomach and intestine are considered as bioaccessible and results from routine analyses of the total PTE content in soils, therefore, are not necessarily related to the degree of bioaccessibility. Experimental methods to determine bioaccessibility usually are time-consuming and relatively complicated in terms of analytical procedures which limits application in first tier assessments. In this study we evaluated the potential suitability of a recently developed single extract method (ISO-17586:2016) using dilute (0.43M) nitric acid (HNO3) to mimic the bioaccessible fraction of PTEs in soils. Results from 204 soils from Portugal, Brazil and the Netherlands including all major soil types and a wide range of PTEs' concentrations showed that the extraction efficiency using 0.43M HNO3 of Ba, Cd, Cu, Ni, Pb and Zn in soils is related to that of in vitro methods including the Simple Bioaccessibility Extraction Test (SBET) and Unified BARGE Method (UBM). Also, differences in the degree of bioaccessibility resulting from differences in parent material, geology and climate conditions did not affect the response of the 0.43M HNO3 extraction which is a prerequisite to be able to compare results from different soils. The use of 0.43M HNO3 as a first screening of bioaccessibility therefore offers a robust and representative way to be included in first tier standard soil tests to estimate the oral bioaccessibility. CapsuleThe single dilute (0.43M) nitric acid extraction can be used in first tier soil risk assessment to assess both geochemical reactivity and oral bioaccessibility of PTEs.